'Previously on World of Warcraft...'

Hello citizens of Azeroth!

I heard the Radiant Song (I believe it is called) and have returned to wow since Legion. Now I've always been a big lore nerd and loved the class hall campaigns.

I stopped playing because of life and I'm now seeking on a catch up explanation of what happened in between Legion and TWW. I followed some of BfA and really loved the stories of the zones and Wrathion and mfing N'zoth but I've read that the expansion was received poorly unfortunately. So I stopped tracking as well

I know SL was a flop so spare me the details but what has been the deal with the Dragon Isles, and how did one thing lead to another?